Process of making abrasive disks



Dec. 16, 1930. A. J. Dol-:RlviANNV PROCESS OF MAKING ABRASIVE DISKS 'Filed Aug-L Original Filed Aug. 12, 1927 Patented Dec. 16, 1930 UNITED STATES ALBERT J'. DOERMANN, OF CHICAGO, ILLINOIS IEJtOCIES-` I?? MAKING ABRASIVE DISKS REISSUED Application IedAAugust 12, 1927. Serial No. 212,550.

This invention relates to improvements in the process of making abrasive disks, and more especially such disks composed of powdered abrasive and cement. For example,

' the abrasive may consist of ground or powdered carbo1undum,emery, flint or any similar suitable substance and be bound together by any suitable cement such as, for example,

A bakelite resin.

Heretofore in manufacturing abrasive disks of this type difficulty has been encountered is obtaining a firm union between the particles of abrasive and the cement.' By the use of my invention I produce a disk with a uniformly agglomerated mixture without any relatively hard or soft spots in the finished material.

Another feature of my invention is the provision of means for fastening a backing on the disk.

Other features and advantages of my invention will appear more fully as I proceed with my specification.

In the drawings accompanying this application, Figure l is a view in perspective of a mold showing a disk cast or molded therein, Fig. 2 is a vertical sectional view of the device shown in Fig. l, Fig. 3 is a view similar to Fig. 2 showing a method of applyingthe 3G backing to the disk, Fig. 4 is a view similar to Fig. 2 showing a method of producing on the back of the disk a relatively smooth, hard surface for the purpose of applying a backing thereto, Fig. 42L is a vievvr showing the method of applying the packing to the disk of Fig. 4, Fig. 5 is a view similar to Fig. 41'showing anolher method of applying a backing to the dis In the practice of my invention, I take suitable proportions of abrasive and cement. For example, I may use ten pounds of abrasive Ato from sixteen to twenty-six ounces-of bakelite resin. c The resin is preferably finely'- powdered before being melted.

lIn the practice of my invention I first take the proper amount of powdered abrasive and treat the same with a suitable hard drying oil, for example, Chinawood or tongwood oil, coating the abrasive grains in this manner assists in causing the cement to adhere to the oil such as a Chinawood or tongwood oil is lbacking must besome non-combustible masaine. By regulating the amount of oil used also maybe procured.

After the grains of abrasive have thus been coated with hard drying oil to the proper extent, the proper amount of powdered bakelite resin with other cement is added and the same thoroughly miXed.

I have found that the use of a hard drying far superior to coatings such as cresote such as has heretofore been employed.

After the coating 0fl the abrasive with the oil and the addition of the bakelite resin and the mixing, the mixture is ready to be placed in a form for forming the disk. This is shown in Figs. l and 2, where 10 indicates the mold and l1 the mixture of abrasive and cement. After the mixtureis spreadevenly in the mold the same may be ironed in with anv ordinary plasterers trowel and then struck off with an ordinary slicing'bar and isthen ready for t-he oven. y

The material is then placed in an oven and baked at a proper temperature, in the usual manner, for a sufficient length of time, as is well known in the art, preferably without the use of any pressure.

I shall now describe the different methods for-placing a backing on the disk. Such a backing, it is to be understood, may be madeeither ofcloth, paper, met-al, or any other suitable material and may be either a plain sheet, perforated', or woven metal, depending upon the use for which the disk is intended.

In Fig. 3 I have shown a method of placingon the disk a backing at the same ltime that the disk is` molded. As here shown, the

terial, for example woven asbestos fabric. A sheet of this material as indicated by 12 is first placed in the mold l() and then a thin layer 13 of powdered resin dusted on. The miXt-ureof abrasive and cement as indicated by 11 is then placed on top. The whole is then baked in the usual manner. and the baking causes the backing l2 to adhere firmly to the disk. i j

In the method shown in Figs. 4 and 4a,

there is first placed. in the mold 10 a layer 10U 14 of very-fine abrasive mixed with resin. A to the wet surface of the mixture of abrasive and cement is then placed and baking the mlxture.

on top. The whole is'then baked. Y

grainsA of abrasive,

In witness whereof, I have hereunto set When the disk is removed from the mold my hand thi it will be seen that the layer 14 vforms on the back a very smooth, hard surface especially adapted for receiving a backing. A backing of any suitable material as indicated by 15 in Fig. lBruay then be cemented onto the smooth surface 14 by means of a layer ofsuitable cement 16 which may be, for example, air drying cement such as silicate of soda or any mixture of magnesium oxide and .magnesium` chloride. If desired, ,the cement 14 may be bakelite `cement and in such case the disk and backing will have to be baked again to make the backing adhere.- In ,such case, of course, the backing 15 must be some noncombustible material. f

' In,Fig. 5 I have shown another method of fastening a backing to the disk 11. In the practice of'this method, the disk is formed as shown in Figs. 1 and 2. One surface of the disk is then coated with any hard cement, air drying filler, such as, for example, iron cement as ,indicated by 17. This gives a very smooth surface to one side of the disk. On topV ofthis smooth surface there `is then applieda layer 18 of cement which may be, for

example, any air drying cement such as sili- A cate of soda or a mixture of magnesium oxide and magnesium' chloride. The backing 19 is then placed on and held'on the disk by means ofthe layerr of cement 18. If desired, the layer of cement 18 may be a bakelite resin cement which requires baking,` and if such, of course, the backing 19 must-be some noncombustible material.

Another advantage in the vuse of ChinawoodV or tongwoodl oil `over creosote is that the former gives oli? no obnoxious fumes, and

also dries harder than creosote.

While I have shown and described certain I embodiments of my invention, it is to' be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement maybe made without What I claim as new, and desire to. secure,

by Letters Patent, is:

1. 'Ihe process of making an abrasive disk comprising, ixings powdered abrasive and bakelite cem'en placing the same in a mold" with alayer of inelypowdered abrasive on `the bottom, and baking thesame:

2. The process of making an abrasive disk consisting of treating powdered abrasive with Chinalwood oil to wet the grains, mixing powdered bakelite resin cement with the Wet. grains of abrasive tocause the same to become coated with grains ofcement adhering s 9th day of August, 1927. ALBERT J. DOERMANN. 

